Sheet discharging apparatus

ABSTRACT

Plural conveying roller pairs are disposed on a conveying path, and plural sheets arranged zigzag are conveyed upwards. At an exit of the conveying path is disposed a movable guide plate to whose forward end a push roller is attached. The movable guide plate is in a horizontal state while the push roller contacts to the drive roller. The sheet in being conveyed upward by a last conveying roller pushes up the movable guide plate. When a rear end of the sheet passes-the last conveying roller, the movable guide plate moves back by its own weight. The sheet is discharged from the conveying path at high speed by the push roller and the drive roller.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a sheet discharging apparatusused in a printer processor, an automatic development system, an imagerecording equipment and the like, and particularly to a sheetdischarging apparatus for discharging recording sheets arranged inzigzag among rows so as to align in one row.

[0003] 2. Description Related to the Prior Art

[0004] In a printer processor used in a photolaboratory is used a paperroll in which a continuous photosensitive recording paper is rolled. Thephotosensitive recording paper which is advanced from the paper roll iscut into recording sheets, and each recording paper is exposed so as toform an image. In the printer processor, thereafter, the recording sheetis conveyed to a development device in which the development and thefixation are made and a dryer in which the drying is made. As therecording sheet, there are a photosensitive recording sheet, normalpaper sheet, and the like. And the recording sheet is simply called asheet.

[0005] Compared with the exposing treatment for exposing and recordingthe image, a long time period is necessary to perform the developingtreatment of one sheet, since during the developing treatment the sheetis conveyed through processing tanks which respectively contain waterand processing liquids for color development, bleaching, fixation, wash,and stabilization. Accordingly, before the developing treatment in thepressing device or development/fixation device, plural exposed sheetsare dispensed so as to lie in zigzag among the plural rows in theconveying path such that the sheet of the latter exposure may bepositioned behind that of the former exposure. Then the exposed sheetsare conveyed to the development/fixation device. As the development ismade after the zigzag arrangement of the sheets in plural rows on theconveying path, the facility of the treatment becomes larger in the sametreatment period. Further, the sheet after the developing treatment isconveyed in the plural rows, and supplied in the dryer. In the dryer, anair heated by a heater is blown with fans so as to dry the sheet.

[0006] Otherwise, after the developing treatment and the dryingtreatment, the sheets discharged in plural rows as described above aregathered into a dispenser with the arrangement in a single row of thesheets in the order of the exposure. For example, Japanese Patents No.3286598 (Pages 1-2), 2812143 (Pages 1-2), and Japanese Patent Laid-OpenPublication No. 2000-3018 (Pages 2-4) describe sheet dischargingapparatuses, in each of which the sheets conveyed in the plural rows aredischarged and arranged in a single row in the order of the exposure.

[0007] In the sheet discharging apparatus described in the above threepublications and the Japanese Patent Publication No. 60-23343, there area conveying section for conveying the plural sheets arranged in pluralrows in the conveying path, a discharging means for discharging out at ahigh speed the sheets which are conveyed in the plural rows, and aconveyer whose endless belt continuously shifts in a directionperpendicular to the discharging direction of the discharging means andreceives the sheets discharged by the discharging means. When the sheetsare discharged onto the belt, they reach sequentially in the order ofthe exposure, and therefore they are conveyed on the endless belt in thesingle row.

[0008] In such sheet discharging apparatus, when the sheet is dischargedat a high speed to the endless belt by the discharging means, the rearedge or upstream edge of the sheet is nipped by a roller pair forconveying the sheet in the plural rows, and there is a differencebetween the conveying speed of the roller pair and the discharging speedof the discharging means. Accordingly, in order to discharge at highspeed to the endless belt, it is necessary to eliminate for thedifference. In the above publications No. 3286598 and 2812143, the sheetdischarging apparatus is provided with a one-way clutch between aconveyer roller of the roller pair disposed along the plural rows and ashaft for coaxially supporting the conveyer rollers. When thedischarging at the high speed to the endless belt is performed, theone-way clutch effects to release the conveyer roller from the drivingsystem. Thus the conveyer roller freely rotates such that the sheet maysmoothly leave the roller pair.

[0009] However, in order to eliminate for the difference between theconveying speed of the conveying roller and the discharging speed by thedischarging means in this structure of free rotation of the conveyingroller in effect of the one-way clutch, the large number of the one-wayclutch is provided in accordance with the length variation of the cutsheet to be used in the above sheet discharging apparatus. As theone-way clutch is expensive, the low cost for production is difficult.Further, when a bending moment is biased to a roller shaft, the one-wayclutch is easily broken. In order to prevent the break of the one-wayclutch, the diameter of the roller shaft is so large that the bend ofthe roller shaft may have no influence on the one-way clutch, andotherwise a shaft bearing is provided to support both side ends of theroller shaft against radial load of the side ends. Accordingly, the costbecomes higher.

[0010] In the publication No. 2000-3018, a high-speed discharging rollerpair constructing a high speed discharging means is constructed of adrive roller and a free roller (pinch roller). As the free roller canslip on the drive roller, the difference of the speed is eliminated.However, in this case, when the sheet is discharged, the free rollerslips on the sheet. Accordingly, the photosensitive compounds on thesheet is rub out off and adhere to the rollers, and otherwise thecompounds of the development solution adhere to the free roller.Therefore, it is necessary to often make the cleaning and themaintenance of the roller. Furthermore, as the free roller slips on thesheet, the abrasion of the surface of the free roller can occur.Accordingly, when the recording paper is discharged to the endless belt,a high speed discharging roller pair often cannot nip the sheet with auniform nip force. Further, when the free roller slips on the sheet, thesheet is often damaged with scratch or the like. The damage of thesurface for forming an image makes the quality of the sheet extremelylower. Furthermore, a clutch mechanism which is constructed of asolenoid and a pair of clutch plates may be used as in the publicationNo. 60-23343, and a torque limiter mechanism may be used as in thepublication No. 2765652. In these cases, however, the number of theparts becomes larger, and many controlling means are necessary, whichprevents the decrease of the cost.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a sheetdischarging apparatus for discharging out a sheet at a high speed with adischarging device, while the sheet is smoothly discharged without aone-way clutch, for eliminating a difference between a conveying speedin a conveying path and a discharging speed with the discharging device.

[0012] Another object of the present invention is to provide a sheetdischarging apparatus in which it is prevented that the sheet isscratched, and the maintenance of a roller is easy.

[0013] Still another object of the present invention is to provide asheet discharging apparatus whose maintenance and structure is simple.

[0014] In order to achieve the object and the other object, a sheetdischarging apparatus of the present invention includes a conveyor forconveying a sheet on a conveying path, a discharging device fordischarging out the sheet, and a pushing device. The discharging deviceis positioned at an exit of the conveying path. When a rear end orupstream end of the sheet leaves the conveyor, a pushing device allowsthe discharging device to discharge the sheet by pushing the sheettoward the discharging device. The discharging speed of the dischargingdevice is higher than a conveying speed of the conveyor.

[0015] The pushing device shifts between a push position and aretracting position. While the sheet is conveyed by the conveyor, thesheet pushes the pushing device to retract in the retracting position.When the sheet leaves the conveyor, the pushing device shifts back to apush position by effect of the gravity.

[0016] In a preferable embodiment, the pushing device has a swingablemember and a push roller attached to the swingable member. Thedischarging device has a drive roller, and the drive roller and the pushroller nip and discharge the sheet. A middle of a periphery of the driveroller is retracted to have a curve.

[0017] Further, the conveyor is a conveying roller pair for nipping andconveying the sheet. One roller of the conveying roller pair is aprotruding roller whose periphery has a protruding middle portion, andanother roller is a retracting roller whose periphery has a recesscorresponding to the shape of the protruding roller. When nipped by theconvey roller pair, the sheet is curled to increase the rigidity.

[0018] According to the sheet discharging apparatus of the presentinvention, the discharging device is positioned at an exit of theconveying path, and the pushing device pushes the sheet to thedischarging device when the rear end of the sheet leaves the conveyor.Thus, the difference between the conveying speed of the conveyor and thedischarging speed of the discharging device is eliminated. Accordingly,the sheet is hardly scratched.

[0019] Further, the pushing device shifts between the push position andthe retracting position, and until the rear end of the sheet leaves fromthe sheet conveyor, the sheet does not contact to the dischargingdevice. Accordingly, the sheet is smoothly discharged with a uniform nipforce.

[0020] After the sheet passes the sheet conveyor, the sheet is pushed tothe sheet discharging device by the pushing device, and nipped at auniform nip force between these means. Thus the sheet is smoothlydischarged at the high speed.

[0021] The discharging device has the drive roller whose the peripheryis retracted in a middle portion. Accordingly when the pushing deviceswings to the push position, the sheet is easily received by the driveroller, and the irregular discharging of the sheet is prevented.

[0022] The conveyor is the convey roller pair, one roller of theconveying roller pair is a protruding roller whose periphery has aprotruding middle portion, and another roller is a retracting rollerwhose periphery has a retracting middle portion corresponding to theshape of the protruding roller. The sheet is curled to have agutter-like shape. Accordingly, the rigidity of the sheet becomeshigher, and pushing device can be easily swung to the retractingposition.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above objects and advantages of the present invention willbecome easily understood by one of ordinary skill in the art when thefollowing detailed description would be read in connection with theaccompanying drawings:

[0024]FIG. 1 is a schematic diagram of a printer processor including asheet discharging apparatus of the present invention;

[0025]FIGS. 2A, 2B are explanatory views illustrating a situation ofdispensing sheets with the sheet dispenser;

[0026]FIG. 3 is a perspective view from the side of an exit of the sheetdischarging apparatus;

[0027]FIG. 4 is a perspective view from another side of the sheetdischarging apparatus;

[0028]FIG. 5 is a side view of the sheet discharging apparatus;

[0029]FIG. 6 is a plan view of a conveyer roller pair for forming curl;

[0030]FIG. 7 is a plan view of a friction juncture section;

[0031]FIGS. 8A-8D are explanatory view illustrating a movement when thesheet is conveyed toward the high speed discharging roller.

PREFERRED EMBODIMENTS OF THE INVENTION

[0032] As shown in FIG. 1, a printer processor 2 is constructed of aprinter section 3 and a processor section 4. The printer section 3 isconstructed of magazines 5, 6, a cutter 7, a back printer 8, an exposuredevice 9, and a sheet dispenser 10. The magazines 5, 6 respectivelycontain rolls of color photographic papers (hereinafter, papers) 11, 12having different width. When a feed roller 13 rotates, the paper 11 isdrawn from the magazine 5, and the cutter 7 cuts the paper 11 inaccordance with a print size to obtain a cut sheet paper, for example,an L-size sheet (width 89 mm×length 127 mm), a 2L-size sheet (width 127mm×length 178 mm). When a feed roller 14 rotates, the paper 12 is drawnfrom the magazine 6, and the cutter 7 cuts the paper 12 in accordancewith a print size to obtain the cut sheet paper, for example, an A4-sizesheet (width 210 mm×length 297 mm). Usually, when an order of theprinting is made in the photofinisher, one of the print sizes of thesheets is selected such that the development may be effectivelyperformed. Accordingly, the change of the print size is usually madecorresponding to that of the order. Further, there are several printsizes in one order of the printing. In this case, the printing of thesheet of the same print size is continuously made.

[0033] In the back printer 8, necessary information, such as a framenumber, a correction data and the like, is printed on the rear surfaceof the sheet 16, 17. In the exposure device 9, a laser printer, digitalvideo printer or the like already known is contained, and an exposure ofthe sheet 16, 17 is made on the basis of the image data sent from animage reading device, or that memorized in a image data memory providedin the exposure device 9.

[0034] As shown in FIGS. 2A-2C, the sheet dispenser 10 dispenses thesheets 16 as a small size sheet (89×127 mm) and the sheet 17 as thelarge size sheet (210×297 mm) into one or plural rows in accordance withthe sheet size. In this situation, each sheet 16, 17 is sent to aprocessing device or development/fixation device 18 and the dryer 19.

[0035] As shown in FIG.2A, the sheets 16 dispensed by the sheetdispenser 10 are arranged zigzag, or in a regularly offset state in tworows on first-third paths 21-23. At first the one sheet 16 is dispensedso as to be on the first and two paths 21, 22, and thereafter theanother sheet 16 is dispensed so as to be on the second and third paths22, 23 behind with difference of a half of the length of the one sheet16. The dispensation is repeated to arrange the sheets 16 zigzag in tworow on the first-third paths 21-23.

[0036] As shown in FIG. 2B, the sheet 17 is not sorted but deposited andconveyed in one row on all over the first-third paths 21-23.

[0037] In this embodiment, the sheet size of each small and large sizesheet is not restricted in the above description. The sheet having thewidth at least 89 mm and at most 152 mm and the length of at least 82.5mm and at most 254 mm is regarded as the small size sheet. The sheethaving the width more than 152 mm or the length more than 254 mm isregarded as the large size sheet. However, in the present invention, thedetermination and the sort of the sheet size are not restricted in them.Further, the sheets having a peculiar sheet size, for example, a testprint paper for management of exposure, a splice sheet which is cut offfrom the spliced paper, are regarded as the sheet 17. Further, after themagazines 5, 6 are set, an front end or downstream end of the paper iscut off and conveyed. However, the front end is not used as a productfor the photo print. Accordingly the front end is also conveyed with thesame manner as the large size sheet.

[0038] After being dispensed in one or plural rows by the sheetdispenser 10, the sheets 16, 17 are conveyed to the development/fixationdevice 18 and the dryer 19 with keeping the arrangement pattern providedat dispensation.

[0039] As shown in FIG. 1, the processor section 4 is constructed of thedevelopment/fixation device 18, the dryer 19, a sheet dischargingapparatus 25, and a sorter machine 26 (see, FIG. 3). Thedevelopment/fixation device 18 is provided with a developing tank 28, ableaching/fixing tank 29 and a washing tank group 34, which hasfirst-fourth washing tanks 30-33 in this order from the upstream side ofthe convey of the sheets 16, 17. The developing tank 28, the fixing tank29 and the washing tanks 30-33 respectively contain a developing liquid,a fixing liquid and a washing water at a predetermined amount. Thesheets 16, 17 are conveyed through the developing, fixing and washingtanks 28-33 with a drive of a conveying rack provided in the developing,fixing and washing tanks 28-33, such that the development is performed.Note that submerged nipping devices are provided in the first-fourthwashing tanks 30-33 through which the sheets 16, 17 are conveyedhorizontally. The conveying rack may have the squeezing devices outsidebetween the developing and the fixing tanks 28, 29.

[0040] The dryer 19 is disposed above the tanks 28-33, and constructedof a conveying belt and an air blowing duct (not shown). The air blowingduct feeds towards the conveying belt an air heated by a heater, so asto press each sheet to the conveying belt. In this situation that eachsheet is conveyed on the conveying belt, each sheet is dried. The driedsheet is thereafter conveyed to the sheet discharging apparatus.

[0041] As shown in FIGS. 3-5, the sheet discharging apparatus 25 isconstructed of a sorting device 36 and a reversibly conveying device 37,or transferring device and controlled by a system controller 38. Thesorting device 36 includes a main body 43 having side plates 41, 42. Inthe main body 43, there are a primary conveying path 44 and a secondarypath 45. Note that the main body 43 has an upper plate for covering theinside of the main body 43, actually. However the upper plate is notillustrated for easiness of FIGS. 3, 4.

[0042] The main body 43, as shown in FIG. 5, has an entrance 46 in alower surface and an exit 47 in an upper surface. The sheets 16, 17which are conveyed in the passages 21-23 from the dryer 19 enter themain body 43 through the entrance 46, and the sheet 16 exits from themain body through the exit 47. Further, there is an exit 48 fordischarging out the sheet 17 at a position below the exit 47.

[0043] In the primary path 44, there are first-third conveying rollerpairs 49-51, a push frame 52, a high speed discharging roller 53 betweenthe entrance 46 and the exit 47. The primary path 44 is directed upwardsnear the entrance 46, and curves so as to extend horizontally. Thesheets 16 are discharged in a horizontal direction from the exit 47 tothe reversibly conveying device 37.

[0044] The first-third convey roller pairs 49-51 are arranged such thatthe primary path 44 may gradually curve from the upside to thehorizontal direction, and the sheets 16 are conveyed at the third conveyroller pair in a direction inclined to the horizontal direction. Thehigh speed discharging roller 53 is positioned at an exit of the primarypath 44. Further, a conveying guide 54 is disposed among the first-thirdconvey rollers from the entrance 46 to the exit 47 around the primarypath 44, such that the fornt edge of the sheet 16 conveyed from theupstream side in the primary path 44 may be guided to the convey rollerpairs 49-51 downstream of the sheet.

[0045] Each of the first and second convey roller pairs 49, 50 isconstructed of a drive roller 56 and a nip roller 57. The drive roller56 and the nip roller 57 are attached to a metallic driving shaft 56 aand a metallic driven shaft 57 a. Both end portions of each driving anddriven shaft 56 a, 57 a are supported by the side plates 41, 42. Thedrive roller 56 may be formed from rubber and have a pillar shape. Thenip roller 57 is formed from a synthetic polymer so as to have thealmost same shape as the drive roller 56.

[0046] As shown in FIG. 6, the third conveying roller pair 51 forforming curl, is constructed of a pair of a nip roller 59 and a driveroller 60. The nip roller 59 is positioned in upper side of the primarypath 44, and attached to a metallic driven shaft 59 a. The nip roller 59has a projecting portion 59 b which is projected in a middle of aperiphery for contacting the sheets 16.

[0047] The drive roller 60 is positioned in a lower side and attached toa metallic driving shaft 60 a. The drive roller 60 has in a middle of aperiphery a retracting portion 60 b which is retracted so as to confrontto the nip roller 59. As described below, the third convey roller pair51 nips and conveys the sheet 16 so as to provide it with a curl shapehaving an arc shape in accordance with the shape of the protrudingportion 59 b and the retracting portion 60 b. While the sheet 16 isconveyed in the primary path 44, a photosensitive layer is positioned inupper side, and as emulsion contained in the photosensitive layer of thesheet 16 is dried, the photosensitive layer shrinks. Accordingly, thenip of the third convey roller pair 51 can easily provide the curl forthe sheet 16.

[0048] One of the end portions of each driving shaft 56 a, 60 a in thefirst-third convey roller pairs 49-51 is protruded from the side plate41, and has a timing pulley 63 fixed thereto. A loop of a timing belt 66mechanically combines the plural timing pulleys 63 with a pinionintegrally formed with the driving shaft 64. Further, the driving shaft64 is connected through a pin clutch with a motor 67 as a source of adrive force. Accordingly, the drive force of the motor 67 is transmittedto rotate the driving shaft 64, and then the rotation of the drivingshaft 64 is transmitted through the timing belt 66 to simultaneouslyrotate the drive rollers 56, 60.

[0049] The nip rollers 57, 59 respectively paired with the drive rollers56, 60 are idly rotatable, and contacted to the drive rollers 56, 60 torotate corresponding to rotation of the drive rollers 56, 60. Since thedrive rollers 56, 60 and the nip rollers 57, 59 are respectively pairedas described above, the nip rollers 57, 59 rotate corresponding torotation of the drive rollers 56, 60, and the sheet 16 is nipped betweenthe drive rollers 56, 60 and the nip rollers 57, 59 and conveyed in theprimary path 44.

[0050] The high speed discharging roller 53 disposed near the exit 47 ofthe primary path 44 has plural rubber rolls 71 having a large diameter.The rubber rolls 71 are attached at a predetermined interval to ametallic driving shaft 70. Both end portions of the driving shaft 70 aresupported by side plates 41, 42. One of the end portions of each drivingshaft 70 is protruded from the side plate 41, and has a pinion 72 fixedthereto. The pinion 72 is meshed with a gear 73 having a largerdiameter. A rotational speed of the gear 73 is variable through a pinclutch, a speed changer and the like. The rotation of the gear 73 iscontrolled such that the rotational speed may be the same between thegear and each drive roller 56, 60. Further, as the pinion 72 has thesmaller diameter than the gear 73, the speed of rotation of the pinion72 is higher than that of the gear 73. Therefore, the high speeddischarging roller 53 rotates at higher speed than the drive rollers 56,60. Between the high speed discharging roller 53 and the drive roller 60is further disposed a stationary guide plate 74 extending in ahorizontal direction.

[0051] As shown in FIG. 7, a periphery 71 a of the rubber roll 71contacts to the sheet 16 and a middle of the periphery retracts inaccordance with the curled shape of the sheet 16 that is provided by thethird convey roller pair 51.

[0052] The push frame 52 as a pushing means is positioned above the highspeed discharging roller 53, and constructed of a swingable guide plate75 and a push roller 76 supported at an end of the swingable guide plate75. The push roller 76 is constructed of a metallic shaft 76 a and arubber roll 76 b which has a large diameter and is firmly attached tothe metallic shaft 76 a. The shaft 76 a is rotatably attached to the endof the swingable guide plate 75.

[0053] The swingable guide plate 75 is supported with the driven shaft59 a which constructs the third convey roller pair 51, and has aplate-like shape which extends upward from the driven shaft 59 above thehigh speed discharging roller 53. The swingable guide plate is movablebetween a push position (illustrated with a solid line in FIG. 5) and aretracting position (illustrated with a chain double-dashed line in FIG.5). At push position, the push roller 76 pushes the sheet 16 to the highspeed discharging roller 53, and the retracting position, the pushroller 76 leaves from the high speed discharging roller 53. Theswingable guide plate 75 is usually positioned in the push position bythe gravity. In the push position, the sheet 16 is pushed by the weightof the swingable guide plate 75 to contact to the high speed dischargingroller 53, and nipped between the push roller 76 and the high speeddischarging roller 53. Accordingly, the high speed discharging roller 53rotates to discharge the sheets 16 in horizontal direction through theexit 47. Note that the guide plate 75 may be provided with a springhaving a weak biasing force, so as to bias to the push position.

[0054] The secondary path 45 divides from the primary path 44 at a pathexchanger 78, and extends toward the exit 48. The secondary path 45 isprovided with plural conveying roller pairs 79, 80 between the pathexchanger 78 and the exit 48. The convey roller pairs 79, 80 arearranged in line on the secondary path 45. The convey roller pairs 79,80 have the same structure as each first and second convey roller pair49, 50. As shown in FIG. 5, a timing pulley 81 is firmly provided on oneend of each shaft to which drive rollers of the convey roller pairs 79,80 are attached. A timing belt 84 surrounds and contacts the pluraltiming pulleys 81, a pinion integrally formed with the drive shaft 82.Further, the driving shaft 82 is connected with the motor 67 in the samemanner as the driving shaft 64. Accordingly, the drive force of themotor 67 is transmitted to rotate the driving shaft 82, and then therotation of the driving shaft 82 is transmitted through the timing belt84 to simultaneously rotate the drive rollers.

[0055] The path exchanger 78 effectively exchanges the conveying pathbetween the normal and particular paths 44, 45, when a guide member 84of the path exchanger 78 is driven by a solenoid 86. The guide member 85has a first guide surface 85 a for guiding to the primary path 45 and asecond guide surface 85 b for guiding to the secondary path 45.

[0056] When the sheet 16 dried in the dryer 19 is supplied through theentrance 46 into the sorting device 36, the sheet 16 is guided to theprimary path 44. When the sheet 17 is supplied through the entrance 46into the sorting device 36, the sheet 17 is guided to and conveyed onthe secondary path 45. Thereafter, the sheet is discharged through theexit 48, and gathered in a tray 126 fixed to the processor section 4.

[0057] The sheet 16 conveyed to the primary path 44 is dischargedthrough the exit 47 to the reversibly conveying device 37 by the highspeed discharging roller 53. The reversibly conveying device 37 isdisposed next to the exit 47, and constructed of a receiver unit 87 anda transferring unit 88 so as to reverse the sheet 16 between front andrear surfaces thereof.

[0058] The receiver unit 87 has a wide endless belt 90 and first andsecond rollers 92, 94. The first and second rollers 92, 94 contact to aninner side of the endless belt 90. The first rotational roller 92 has arelatively small diameter. The first roller 92, whose both ends arerotatably supported, is disposed in an upstream side in the conveyingdirection C of the reversibly conveying device 37. Further, the secondroller 94 has a relatively large diameter, and rotatably disposed inanother side of the first roller 92, namely in a downstream side in theconveying direction C. Accordingly, when the first and second rollers92, 94 rotate, the endless belt 90 shifts on the loop to convey thesupplied sheet 16 in the conveying direction C perpendicular to theconveying direction in the sorting device 36.

[0059] Both ends of the second roller 94 are rotatably supported by aframe (not shown) of the reversibly conveying device 37. One of the endsis protruded on an outer surface of the frame, and connected with adrive motor (not shown) as a source of a drive force. As the drivemotor, there is a pulse motor whose rotational speed is controlled bythe system controller 38. Thus the rotation of the motor is transmittedthrough the second roller 94 to the endless belt supported by the firstand second rollers 92, 94, and the endless belt 90 shift around on theloop formed with support of the first and second rollers 92, 94.

[0060] The pulse motor used as the drive motor is, for example, a typewhich is a changeable variation of a phase excitation type, and rotates0.9 degree of angle per one pulse.

[0061] The transferring unit 88 includes plural thin and narrow belts102, 104, 106, 108 which are arranged in parallel to construct aconveying path. These plural belts 102, 104, 106, 108 (whose number isfour in this embodiment) are supported by first-third rollers 110, 112,114. The first roller 110 is disposed in right and upper side from thesecond roller 94 of the receiver unit 87, the second roller 112 isdisposed in a left and lower side from the second roller 94, and thethird roller 114 is disposed in a lower side from the first roller 92 ofthe receiver unit 87 at the exit of the sorting device 36.

[0062] The first roller 110 has a shaft 118 whose both ends aresupported with the frame. Crown rollers are firmly fitted in respectivegrooves which are formed on a periphery of the first roller 110 atpositions corresponding to the four belts 102, 104, 106, 108. Thus thecrown rollers rotate at the same rotational speed of the shaft 118.Further, the second and third rollers 112, 114 have respective shafts120, 122 supported with the frame and crown rollers at positionscorresponding to the belts 102, 104, 106, 108 on the shafts 120, 122.The crownrollers are fixed to the shafts 120, 122, so as to rotate atthe same rotational speed of the shafts 120, 122.

[0063] Each of the belts 102, 104, 106, 108 forms a loop around on thesupporting first-third rollers 110, 112, 114. Each belt 102, 104, 106,108 is pressed to contact to the first roller 110 such that the eachbelt 102, 104, 106, 108 turns about 180 degrees with the center of thefirst roller 110. Thereafter, the each belt turns to an oppositedirection with the contact to the third roller 114, and then contacts tothe second roller 112 to be bent towards the first roller 110 for anendless form. Thus the conveying path of the sheet 16 is constructed.

[0064] When the sheet 16 is discharged through the exit 47 to thereversibly conveying device 37, the endless belt 90 of the receiver 87continuously moves. Therefore, the discharged sheet 16 is positioned onthe moving endless belt 90, and conveyed. Thus the sheets 16 dischargedfrom the sorting device 36 are arranged in one row and sequentiallyconveyed in the conveying direction C. Then the sheets 16 are sandwichedbetween the endless belt and the belts 102, 104, 106, 108, anddischarged from the upper to the lower side of the second roller 94.Thus the sheets 16 are turned over. Thereafter, the sheet is conveyed onthe belts 102, 104, 106, 108 in the direction B, and supplied through aspace between the first roller and the third roller 114 to a tray 124 ofthe sorter 26.

[0065] The sorter 26 in which the sheets 16 are supplied from thereversibly conveying device 37 has plural trays 124 which are attachedto a shifting means for shifting around on a loop. The trays 124 aresequentially shifted downward from the receiving position at the exit ofthe reversibly conveying device 37, and turned at the lowermost positionto shift to the receiving position. The sheets 16 are discharged throughthe exit between the first roller 92 and the roller 114, and received bythe tray 124 positioned at a receiving position in the lower side of theexit. When the supply of the sheets 16 of the one customer order on thetray 124 is completed, a sort signal is generated, and the tray 124 isshifted downward for one stage, and another empty tray 124 is shiftedfrom an upper side to the receiving position so as to receive the sheets16 of the another customer order. The sheets 16, 17 disposed on the tray124 after the completion of the supply thereof are removed from the tray124 by an operator while the tray 124 is shifted to an lowermostposition.

[0066] Effects of the above structure will be explained now. Note thatthe sheet 16 is taken as an example in the following explanation. Whenthe explanation of the sheet 17 is necessary, they are taken an example.

[0067] The printer processor is turned on, and the operator inputs imagerecording information, such as image data of images to be printed on therecording paper 11, the print size, the number of photo prints and thelike. Then a print start button is pressed to start the recordingprocesses of the image on the paper 11. Then, the paper 11 is drawn fromthe magazine 5, and cut by the cutter 7 to produce the sheet 16. Thenthe sheet 16 is conveyed sequentially through the back printer 8 and theexposure device 9, in which the printing on the back surface and theexposure of the printing surface of the sheet 16 are respectively made.After the print on the back and recording surfaces is completed, thesheet 16 is conveyed to the sheet dispenser 10.

[0068] In the sheet dispenser 10, the sheets 16 are arranged in zigzagon two rows on the basis of predetermined dispensing pattern, andfurther conveyed in this arrangement to the processing devicedevelopment/fixation device 18 and the dryer 19.

[0069] In the development/fixation device 18 and the dryer 19, thedeveloping treatment and the drying treatment of the sheet 16 are made.Thereafter, the sheet 16 is conveyed to the sheet discharging apparatus25. In the sheet discharging apparatus 25, as mentioned above, the sheet16 is conveyed in the primary path 44 and discharged through the exit 47to the endless belt 90. The process for discharging the sheet 16 fromthe primary path 44 to the endless belt 90 is explained in referencewith FIGS. 8A-8C.

[0070] In FIG. 8A, the sheet 16 is conveyed toward the nip roller 59 byrotation of the first-third conveying roller pairs 49-51, in theconveying path curved by the conveying guides 54. As shown in FIG. 8B,the convey direction at the third convey roller pair 51 is inclined withthe inclination angle a to the perpendicular direction. Thereby asnipped with the third convey roller pair 51, the sheet 16 is providedwith the curl having the gutter-like shape. The sheet 16 having thegutter-like curl has a high rigidity in the conveying direction.Accordingly, a front end or downstream end 16 a of the sheet 16 pushesup the swingable guide plate 75, which is shifted from the push positionto the retracting position.

[0071] The sheet 16 is further conveyed with the inclination of theangular a to press the swingable guide plate 75 while nipped by thethird convey roller pair 51. Then as shown in FIG. 8C, a rear end orupstream end 16 b of the sheet 16 reaches the third convey roller pair51.

[0072] The sheet 16 discharged by the third convey roller pair 51 cannotkeep the swingable guide plate 75 in the retracting position.Accordingly, as shown in FIG. 8D, the swingable guide plate 75 swingsback to the push position by its own weight to push the sheet 16 to thehigh speed discharging roller 53, and the high speed discharging roller53 rotates to discharge the sheet 16 in the horizontal direction throughthe exit 47 to the endless belt 90. Thereby, as the periphery 71 a ofthe rubber roll 71 constructing the high speed discharging roller 53 hasa retraction in accordance with the form of the curl of the sheet 16,the high speed discharging roller 53 can receive the sheet 16 to preventthe irregular discharging of the sheet 16. Therefore, the next sheet 16conveyed in another row is discharged at the predetermined intervalafter that in the preceding row. Thus the discharging out of the sheets16 through the exit 47 is made in the order of the zigzag arrangement.Further, the sheets 16 are conveyed in one row on the endless belt 90and the belts 102, 104, 106, 108 toward the tray 124 of the sortermachine 26. In the sorter 26, the sheets 16 are sequentially overlaidand gathered on the one tray 124 for each customer order.

[0073] Thus the sheet 16 conveyed by the first—third convey roller pairs49-51 is pushed by the push frame 52 and discharged to the endless belt90. Accordingly, when the third convey roller pair 51 and the high speeddischarging roller 53 are positioned at a smaller interval than thelength of the sheet 16 in the conveying direction, it is not necessaryto provide a one-way clutch for absorbing the difference between theconveying speed of the third convey roller pair 51 and the dischargingspeed of the high speed discharging roller 53, and the cost forproduction becomes lower. Further, as the slip between the rollers andthe sheet does not occur, the pollution and the abrasion are prevented.Thus the sheet 16 can be discharged with a stable nip force, and themaintenance can be kept more easily.

[0074] Further, the sheet is conveyed with the inclination by the thirdconvey roller pair 51 to swing the swingable guide plate 75 in theretracting position. Therefore before the rear end 16 b of the sheet 16leaves the third convey roller pair 51, the sheet 16 does not contact tothe high speed discharging roller 53. Accordingly, the sheet 16 is notscratched and the discharging speed of the high speed discharging roller53 can be kept for stable conveyance.

[0075] Note that the roller members are fixed to the shaft in theconveying roller pair and the high-speed discharging roller of the aboveembodiment. However, the present invention is not restricted in it, andthe roller members may be slidable along the shaft. In this case, theposition of the roller member is adjusted in accordance with the widthof the sheet and the number of the rows in the conveying path.

[0076] In the above embodiment, the photosensitive material drawn fromthe magazine is cut by the cutter 7 to have a predetermined size. Theposition of the cutter 7 may be upstream from the sheet dispenser 10,and is not restricted in the above embodiment. Further, the cuttingdirection of the cutter 7 is a widthwise direction of the photosensitivematerial, and the print size of the cut sheet depends on the length ofconvey before cutting. Further, in the above embodiment, the width ofthe print size in the widthwise direction is changed by selecting one ofthe plural photosensitive materials which have different width. However,a slitter may be provided so as to cut the photosensitive material inthe conveying direction, and to change the width of the cut recordingmaterial. The number of the magazines is not restricted in two, but maybe equal to or than three.

[0077] Further, in the above embodiment, the sheets 16 conveyed in tworows are discharged and aligned in one row. However, the presentinvention is not restricted in this embodiment, and the sheet may beconveyed with arrangement in at least 3 rows. In this case, the conveyroller pairs 49-51, the push frame 52, the high speed discharging roller53 are disposed on each row.

[0078] In the above embodiment, the present invention is applied to adevice for developing the photosensitive material. However, the presentinvention may be applied to multi-row types of sheet dischargingapparatus in which sheets in plural rows are conveyed. For example, thepresent invention may be applied to an ink jet printer, in which thesheet after printing is conveyed and dried in plural rows.

[0079] Various changes and modifications are possible in the presentinvention and may be understood to be within the present invention.

What is claimed is:
 1. A sheet discharging apparatus, comprising: aconveyor for conveying a sheet on a conveying path; a discharging devicedisposed near an exit of said conveying path for discharging out saidsheet, said discharging device being positioned apart from saidconveyor, a discharging speed of said discharging device being higherthan a conveying speed of said conveyor; a pushing device for allowingsaid discharging device to discharge said sheet by pushing said sheettoward said discharging device, when a rear edge of said sheet passessaid conveyor.
 2. A sheet discharging apparatus as claimed in claim 1,wherein said pushing device is shiftable between a push position inwhich said pushing device pushes said sheet toward said dischargingdevice and a retracting position in which said pushing device leavesfrom said discharging device.
 3. A sheet discharging apparatus asclaimed in claim 2, said pushing device comprising: a guide memberdisposed such that said guide member may be pushed up to said retractingposition; and a push roller attached to said guide member, forcontacting said sheet to said discharging device, when said pushingdevice is in said push position.
 4. A sheet discharging apparatus asclaimed in claim 3, wherein said discharging device is a drive roller,and said drive roller nips and discharges said sheet with said pushroller.
 5. A sheet discharging apparatus as claimed in claim 4, whereinsaid guide member is substantially horizontally in said push position,and said sheet conveyor conveys upward with inclination such that an endof said sheet pushes up said guide member in said push position.
 6. Asheet discharging apparatus as claimed in claim 5, wherein said sheetconveyor is plural conveying roller pairs which are disposed on saidconveying path and include a last conveying roller pair disposed at adownstream end thereof, and said last conveying roller pair includes anupper roller and a lower roller.
 7. A sheet discharging apparatus asclaimed in claim 6, wherein said guide member is swingably attached to ashaft of said upper roller.
 8. A sheet discharging apparatus as claimedin claim 7, wherein a middle of a periphery of said drive roller has aconcavely curved surface.
 9. A sheet discharging apparatus as claimed inclaim 7, wherein said upper roller is a protruding roller whoseperiphery has a convexly curved middle portion, said lower roller is aretracting roller whose periphery has a concavely curved middle portioncorresponding to the shape of said protruding roller, for curling saidsheet.
 10. A sheet discharging apparatus as claimed in claim 9, whereinsaid sheet comprises plural sheets arranged in zigzag among plural rowsin said conveying path.
 11. A sheet discharging apparatus as claimed inclaim 10, further comprising an endless belt for receiving said sheetwhich is discharged by said discharging device, said endless belt beingmoved in a direction perpendicular to a discharging direction of saiddischarging device for arranging said sheet in an row with reversingsaid sheet.